Thank you for beer and bread, yeast. What would we do without you?


My first loaf of bread! White bread with olive oil and basil.

Today I was feeling a little under the weather, so I decided to forego venturing out into the world of holiday traffic and opted to stay home all day. I really don’t remember the last time I’ve had a day to do absolutely nothing. I could finally get to reading, playing guitar, maybe squeeze in a power nap…

Instead, I chose to bake, as baking is something I enjoy immensely yet rarely have the time to really invest tender loving care into. Patience with baking is key, and today I had all the time in the world. Among the usual cookies and fruit tarts that I love making, I chose to take a stab at something I had never made before: bread.

Of course, it is a well-known fact that yeast makes bread rise, but I honestly have never really thought about its mechanism. How does yeast make bread rise?

Yeasts are eukaryotic (multi-cellular) micro-organisms within the fungal species. The species used in baking is usually Saccharomyces cerevisiae and it ferments the sugars present to extract energy and multiply, and consequently produces carbon dioxide and alcohol. The gaseous carbon dioxide formed causes the dough to expand and rise as gas bubbles and air pockets are formed. The ideal temperature for fermentation is 85-90°F, any higher and it will ferment at a rapid rate and produce undesirably large bubbles. When the dough is baked, the yeast dies beginning at about 120°F, the air pockets are set, and the alcohol is evaporated off. The result is the bread’s sponge-like appearance and airy texture. Before commercial yeast was available, bread was allowed to sit outside and would eventually rise by utilizing the natural yeast found in plants and in the air. This same mechanism holds true for fermentation of beer. 

Besides the roughly 2% of micro-organisms that are harmful, the rest are actually pretty damn great to us. Where would we be today without beer and bread, the epitome of college life, football Sundays, family dinners, America, Germany…? Fun fact: Saccharomyces cerevisiae was also the first eukaryotic genome to be completely sequenced, which has provided a major leap in research of the basic molecular biology of humans and other animals.

And by the way, if you know how to operate an oven, you really should consider baking homemade bread. I was entirely shocked at how much better is tasted than even the best store-bought loaf. It was extremely easy to make, and although it was time consuming, the end product was dense yet still light and moist on the inside, crunchy on the outside, flavorful. Really, I don’t think I will every buy store bought bread again. Tomorrow, I’m planning on buying ingredients to make gluten-free bread that I can freeze for future consumption. And with my baking spirits high, I guess it’s time to start thinking about what dessert to make for Christmas!


2 responses to “Thank you for beer and bread, yeast. What would we do without you?

  1. Nice “science of bread” post!

  2. Thank you, glad you enjoyed it. Happy holidays!

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